Java tutorial
/* * Copyright 2000-2018 Vaadin Ltd. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package com.vaadin.client.ui; import java.util.logging.Logger; import com.google.gwt.core.client.GWT; import com.google.gwt.core.client.Scheduler; import com.google.gwt.core.client.Scheduler.ScheduledCommand; import com.google.gwt.dom.client.DivElement; import com.google.gwt.dom.client.Document; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.FormElement; import com.google.gwt.dom.client.InputElement; import com.google.gwt.user.client.Event; import com.google.gwt.user.client.Timer; import com.google.gwt.user.client.ui.FileUpload; import com.google.gwt.user.client.ui.FlowPanel; import com.google.gwt.user.client.ui.FormPanel; import com.google.gwt.user.client.ui.Hidden; import com.google.gwt.user.client.ui.Panel; import com.google.gwt.user.client.ui.SimplePanel; import com.vaadin.client.ApplicationConnection; import com.vaadin.client.BrowserInfo; import com.vaadin.client.ConnectorMap; import com.vaadin.client.StyleConstants; import com.vaadin.client.ui.upload.UploadConnector; import com.vaadin.client.ui.upload.UploadIFrameOnloadStrategy; import com.vaadin.shared.ui.upload.UploadServerRpc; /** * * Note, we are not using GWT FormPanel as we want to listen submitcomplete * events even though the upload component is already detached. * * @author Vaadin Ltd * */ public class VUpload extends SimplePanel { private final class VFileUpload extends FileUpload { @Override public void onBrowserEvent(Event event) { super.onBrowserEvent(event); if (event.getTypeInt() == Event.ONCHANGE) { if (isImmediateMode() && fu.getFilename() != null && !fu.getFilename().isEmpty()) { submit(); } } else if (BrowserInfo.get().isIE() && event.getTypeInt() == Event.ONFOCUS) { // IE and user has clicked on hidden textarea part of upload // field. Manually open file selector, other browsers do it by // default. fireNativeClick(fu.getElement()); // also remove focus to enable hack if user presses cancel // button fireNativeBlur(fu.getElement()); } } } public static final String CLASSNAME = "v-upload"; /** * FileUpload component that opens native OS dialog to select file. * <p> * For internal use only. May be removed or replaced in the future. */ public FileUpload fu = new VFileUpload(); Panel panel = new FlowPanel(); UploadIFrameOnloadStrategy onloadstrategy = GWT.create(UploadIFrameOnloadStrategy.class); /** For internal use only. May be removed or replaced in the future. */ public ApplicationConnection client; /** For internal use only. May be removed or replaced in the future. */ public String paintableId; /** * Button that initiates uploading. * <p> * For internal use only. May be removed or replaced in the future. */ public final VButton submitButton; /** * When expecting big files, programmer may initiate some UI changes when * uploading the file starts. Bit after submitting file we'll visit the * server to check possible changes. * <p> * For internal use only. May be removed or replaced in the future. */ public Timer t; /** * some browsers tries to send form twice if submit is called in button * click handler, some don't submit at all without it, so we need to track * if form is already being submitted */ private boolean submitted = false; private boolean enabled = true; private boolean immediateMode; private String acceptMimeTypes; private Hidden maxfilesize = new Hidden(); /** For internal use only. May be removed or replaced in the future. */ public FormElement element; private com.google.gwt.dom.client.Element synthesizedFrame; /** For internal use only. May be removed or replaced in the future. */ public int nextUploadId; public VUpload() { super(com.google.gwt.dom.client.Document.get().createFormElement()); element = getElement().cast(); setEncoding(getElement(), FormPanel.ENCODING_MULTIPART); element.setMethod(FormPanel.METHOD_POST); setWidget(panel); panel.add(maxfilesize); panel.add(fu); submitButton = new VButton(); submitButton.addClickHandler(event -> { if (isImmediateMode()) { // fire click on upload (e.g. focused button and hit space) fireNativeClick(fu.getElement()); } else { submit(); } }); panel.add(submitButton); setStyleName(CLASSNAME); } private static native void setEncoding(Element form, String encoding) /*-{ form.enctype = encoding; }-*/; /** * Sets the upload in immediate mode. * * @param immediateMode * {@code true} for immediate mode, {@code false} for * non-immediate mode */ public void setImmediateMode(boolean immediateMode) { if (this.immediateMode != immediateMode) { this.immediateMode = immediateMode; if (immediateMode) { fu.sinkEvents(Event.ONCHANGE); fu.sinkEvents(Event.ONFOCUS); } else { fu.unsinkEvents(Event.ONCHANGE); fu.unsinkEvents(Event.ONFOCUS); } } setStyleName(getElement(), CLASSNAME + "-immediate", immediateMode); } /** * Returns whether this component is in immediate mode or not. * * @return {@code true} for immediate mode, {@code false} for not */ public boolean isImmediateMode() { return immediateMode; } private static native void fireNativeClick(Element element) /*-{ element.click(); }-*/; private static native void fireNativeBlur(Element element) /*-{ element.blur(); }-*/; /** For internal use only. May be removed or replaced in the future. */ public void disableUpload() { setEnabledForSubmitButton(false); if (!submitted) { // Cannot disable the fileupload while submitting or the file won't // be submitted at all fu.getElement().setPropertyBoolean("disabled", true); } enabled = false; } /** For internal use only. May be removed or replaced in the future. */ public void enableUpload() { setEnabledForSubmitButton(true); fu.getElement().setPropertyBoolean("disabled", false); enabled = true; if (submitted) { /* * An old request is still in progress (most likely cancelled), * ditching that target frame to make it possible to send a new * file. A new target frame is created later." */ cleanTargetFrame(); rebuildPanel(); submitted = false; } ensureUploadButton(); } private void ensureUploadButton() { // when push got enabled, need to ensure the upload is disabled properly // check ticket #11652 if (fu.getElement().getParentElement().getParentElement().hasClassName("v-disabled")) { disableUpload(); } } private void setEnabledForSubmitButton(boolean enabled) { submitButton.setEnabled(enabled); submitButton.setStyleName(StyleConstants.DISABLED, !enabled); } /** * Re-creates file input field and populates panel. This is needed as we * want to clear existing values from our current file input field. */ private void rebuildPanel() { panel.remove(submitButton); panel.remove(fu); fu = new VFileUpload(); fu.setName(paintableId + "_file"); fu.getElement().setPropertyBoolean("disabled", !enabled); if (acceptMimeTypes != null && !acceptMimeTypes.isEmpty()) { InputElement.as(fu.getElement()).setAccept(acceptMimeTypes); } panel.add(fu); panel.add(submitButton); if (isImmediateMode()) { fu.sinkEvents(Event.ONCHANGE); } } /** * Called by JSNI (hooked via {@link #onloadstrategy}) */ private void onSubmitComplete() { /* Needs to be run dereferred to avoid various browser issues. */ Scheduler.get().scheduleDeferred(() -> { if (submitted) { if (client != null) { if (t != null) { t.cancel(); } getLogger().info("VUpload:Submit complete"); if (isAttached()) { // no need to call poll() if component is already // detached #8728 ((UploadConnector) ConnectorMap.get(client).getConnector(VUpload.this)) .getRpcProxy(UploadServerRpc.class).poll(); } } rebuildPanel(); submitted = false; enableUpload(); if (!isAttached()) { /* * Upload is complete when upload is already abandoned. */ cleanTargetFrame(); } } }); } ScheduledCommand startUploadCmd = () -> { element.submit(); submitted = true; disableUpload(); /* * Visit server a moment after upload has started to see possible * changes from UploadStarted event. Will be cleared on complete. * * Must get the id here as the upload can finish before the timer * expires and in that case nextUploadId has been updated and is wrong. */ final int thisUploadId = nextUploadId; t = new Timer() { @Override public void run() { // Only visit the server if the upload has not already // finished if (thisUploadId == nextUploadId) { getLogger().info("Visiting server to see if upload started event changed UI."); client.updateVariable(paintableId, "pollForStart", thisUploadId, true); } } }; t.schedule(800); }; /** For internal use only. May be removed or replaced in the future. */ public void submit() { if (submitted || !enabled) { getLogger().info("Submit cancelled (disabled or already submitted)"); return; } if (fu.getFilename().isEmpty()) { getLogger().info("Submitting empty selection (no file)"); } // flush possibly pending variable changes, so they will be handled // before upload client.sendPendingVariableChanges(); // This is done as deferred because sendPendingVariableChanges is also // deferred and we want to start the upload only after the changes have // been sent to the server Scheduler.get().scheduleDeferred(startUploadCmd); } /** For internal use only. May be removed or replaced in the future. */ public void disableTitle(boolean disable) { if (disable) { // Disable title attribute for upload element. if (BrowserInfo.get().isChrome()) { // In Chrome title has to be set to " " to make it invisible fu.setTitle(" "); } else if (BrowserInfo.get().isFirefox()) { // In FF title has to be set to empty string to make it // invisible // Method setTitle removes title attribute when it's an empty // string, so setAttribute() should be used here fu.getElement().setAttribute("title", ""); } // For other browsers absent title doesn't show default tooltip for // input element } else { fu.setTitle(null); } } @Override protected void onAttach() { super.onAttach(); if (client != null) { ensureTargetFrame(); } } /** For internal use only. May be removed or replaced in the future. */ public void ensureTargetFrame() { if (synthesizedFrame == null) { // Attach a hidden IFrame to the form. This is the target iframe to // which the form will be submitted. We have to create the iframe // using innerHTML, because setting an iframe's 'name' property // dynamically doesn't work on most browsers. DivElement dummy = Document.get().createDivElement(); dummy.setInnerHTML("<iframe src=\"javascript:''\" name='" + getFrameName() + "' style='position:absolute;width:0;height:0;border:0'>"); synthesizedFrame = dummy.getFirstChildElement(); Document.get().getBody().appendChild(synthesizedFrame); element.setTarget(getFrameName()); onloadstrategy.hookEvents(synthesizedFrame, this); } } private String getFrameName() { return paintableId + "_TGT_FRAME"; } @Override protected void onDetach() { super.onDetach(); if (!submitted) { cleanTargetFrame(); } } private void cleanTargetFrame() { if (synthesizedFrame != null) { Document.get().getBody().removeChild(synthesizedFrame); onloadstrategy.unHookEvents(synthesizedFrame); synthesizedFrame = null; } } private static Logger getLogger() { return Logger.getLogger(VUpload.class.getName()); } public void setAcceptMimeTypes(String acceptMimeTypes) { if (acceptMimeTypes == null || acceptMimeTypes.isEmpty()) { InputElement.as(fu.getElement()).setAccept(null); } else { InputElement.as(fu.getElement()).setAccept(acceptMimeTypes); } this.acceptMimeTypes = acceptMimeTypes; } }